The present disclosure relates to fluid analysis and, more particularly, to methods of calibration transfer to a testing instrument.
In subterranean well drilling and completion, tests on formations penetrated by a wellbore are typically performed in order to determine geological or other physical properties of the formation and fluids contained therein. For example, parameters such as permeability, porosity, fluid resistivity, temperature, pressure and saturation pressure may be determined. These and other characteristics of the formation and fluid contained therein may be determined by performing tests on the formation before the well is completed.
To evaluate prospects of an underground hydrocarbon reserve, a representative sample of the fluid may be captured for detailed analysis. In a typical sampling procedure, a sample of the formation fluids may be obtained by lowering a sampling tool having a sampling chamber into the wellbore on a conveyance such as a wireline, slick line, coiled tubing, jointed tubing or the like. When the sampling tool reaches the desired depth, one or more ports are opened to allow collection of the formation fluids. The ports may be actuated in a variety of ways such as by electrical, hydraulic or mechanical methods. Once the ports are opened, formation fluids travel through the ports and a sample of the formation fluids is collected within the sampling chamber of the sampling tool. After the sample has been collected, the formation fluid sample may be analyzed.
Competitive reservoir formation testing requires determination of primary fluid components in the field. A filter spectrometer may be built into a downhole tool to generate a sample spectrum, and a data processor may be used based on calibrated multivariate predictive models. However, multivariate calibration of multiple instruments can be a challenge, as the calibration can be very sensitive to small variations in the wavelengths and absorbance, for example. The calibrations developed on one instrument at a standard calibration lab, for example, can generally not transfer to a second instrument of the same type to be used in the field without some adjustment to either the spectral data or the calibration. Accordingly, there is a need for robust calibration transfer to effectively address these challenges.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.